U.S. patent application number 10/520859 was filed with the patent office on 2006-05-25 for low-pressure mercury lamp and method for assembling the same.
Invention is credited to Shiro Iida, Kenji Itaya, Yoshinori Kakuno, Akiko Nakanishi.
Application Number | 20060108908 10/520859 |
Document ID | / |
Family ID | 30767821 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060108908 |
Kind Code |
A1 |
Nakanishi; Akiko ; et
al. |
May 25, 2006 |
Low-pressure mercury lamp and method for assembling the same
Abstract
An arc tube is formed by a glass tube that is turned at a
substantially middle thereof and wound around a spiral axis from
the middle, to have a double-spiral structure. End portions of the
arc tub are wound around the spiral axis. A holder has insertion
openings formed therein in such shapes that correspond to shapes of
the ends of the arc tube. The insertion openings allow the ends of
the arc tube to be inserted along a bottom wall of the holder. The
holder also includes guide grooves provided in the areas before the
insertion openings in the spiral direction of the ends of the arc
tube. The guide grooves allow the end portions of the arc tube to
come in contact, and when the arc tube is rotated around the axis,
guide the ends of the arc tube to the insertion openings.
Inventors: |
Nakanishi; Akiko;
(Takatsuki-shi, JP) ; Kakuno; Yoshinori;
(Katano-shi, JP) ; Iida; Shiro; (Kyoto-shi,
JP) ; Itaya; Kenji; (Takatsuki-shi, JP) |
Correspondence
Address: |
SNELL & WILMER LLP
600 ANTON BOULEVARD
SUITE 1400
COSTA MESA
CA
92626
US
|
Family ID: |
30767821 |
Appl. No.: |
10/520859 |
Filed: |
July 22, 2003 |
PCT Filed: |
July 22, 2003 |
PCT NO: |
PCT/JP03/09234 |
371 Date: |
October 3, 2005 |
Current U.S.
Class: |
313/318.01 |
Current CPC
Class: |
H01J 61/72 20130101;
H01J 5/48 20130101; H01J 9/247 20130101 |
Class at
Publication: |
313/318.01 |
International
Class: |
H01J 5/48 20060101
H01J005/48 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 22, 2002 |
JP |
2002-212911 |
Claims
1. A low-pressure mercury lamp, comprising: an arc tube whose at
least one end is wound around an axis entirely in a longitudinal
direction thereof; and a holding member that holds the arc tube in
a state where the at least one end is inserted in an opening formed
in the holding member, wherein the holding member includes an
insertion-guiding unit for guiding the at least one end of the arc
tube to be inserted into the opening while preventing positional
deviation of the at least one end, when the arc tube is rotated
around the axis to be attached to the holding member.
2. The low-pressure mercury lamp of claim 1, wherein the
insertion-guiding unit is formed as a groove extending in a
direction in which the end of the arc tube is wound around the
axis.
3. The low-pressure mercury lamp of claim 2, wherein a part of the
groove that comes in contact with a part of the end of the arc tube
has a shape corresponding to a shape of the part of the end of the
arc tube.
4. The low-pressure mercury lamp of claim 1, wherein the arc tube
includes a pair of lead wires for an electrode extending from the
end of the arc tube, the opening opens toward a direction of the
axis, and the holding member allows the pair of lead wires to be
inserted in the opening.
5. The low-pressure mercury lamp of claim 4, wherein the opening is
formed at an angle of 20 to 60.degree. inclusive with respect to
the axis.
6. The low-pressure mercury lamp of claim 4, wherein the holding
member includes a covering unit that is formed so that the opening
is positioned at an edge of the covering unit, the covering unit
covering the end of the arc tube, and the opening is partially
formed by a notch created in the covering unit and/or the
insertion-guiding unit.
7. The low-pressure mercury lamp of claim 1, wherein the end of the
arc tube is bonded within the holding member via a bonding
agent.
8. The low-pressure mercury lamp of claim 7, wherein the
insertion-guiding unit includes one or more inlets for injecting
the bonding agent in an area between (a) the end of the arc tube
placed in the holding member and (b) the insertion-guiding unit of
the holding member.
9. The low-pressure mercury lamp of claim 7, wherein the holding
member includes a wall at an internal surface thereof for
preventing the bonding agent from flowing outside.
10. The low-pressure mercury lamp of claim 1, wherein the arc tube
includes a pair of lead wires for an electrode extending from the
end of the arc tube, and the holding member includes a supporting
unit for supporting the pair of lead wires while keeping a certain
distance between the lead wires.
11. The low-pressure mercury lamp of claim 1, wherein the arc tube
includes a glass tube that is turned at a substantially middle
thereof and wound around the axis from the middle, to have a
double-spiral structure.
12. A method for assembling a low-pressure mercury lamp including:
an arc tube whose at least one end is wound around an axis entirely
in a longitudinal direction thereof; and a holding member that
includes an insertion-guiding unit for guiding the at least one end
of the arc tube to be inserted into an opening formed in the
holding member while preventing positional deviation of the at
least one end, wherein a process of attaching the arc tube to the
holding member includes the steps of: making the at least one end
of the arc tube come in contact, at a peripheral surface thereof,
with the insertion-guiding unit of the holding member; and
rotating, in a state where the at least one end of the arc tube is
in contact with the insertion-guiding unit, the arc tube and/or the
holding member around the axis, so that the arc tube has a relative
position with respect to the opening of the holding member.
13. The method for assembling the low-pressure mercury lamp of
claim 12, wherein the arc tube has a pair of lead wires for an
electrode extending from the end of the arc tube, the opening opens
toward a direction of the axis, and the step of making the at least
one end of the arc tube come in contact with the insertion-guiding
unit of the holding member is carried out in a state where the lead
wires are parallel to the direction of the axis.
Description
TECHNICAL FIELD
[0001] The present invention relates to a low-pressure mercury lamp
that includes a holder holding an arc tube in a state where at
least one end of the arc tube is inserted in an insertion opening
formed in the holder, and a method for assembling the low-pressure
mercury lamp.
BACKGROUND ART
[0002] In the present energy-saving era, a lot of efforts have been
made to develop low-pressure mercury lamps. In particular,
fluorescent lamps, specifically compact self-ballasted fluorescent
lamps that exhibit high luminous efficiency and long life, are
calling attentions as light sources alternative to incandescent
lamps. As one example, compact self-ballasted fluorescent lamps may
include double-spiral arc tubes formed so that end portions stand
vertically and remaining portions are wound in a double spiral
around the axis of spiral.
[0003] Compact self-ballasted fluorescent lamps including such
double-spiral arc tubes have a higher total height than that of
incandescent lamps. The problem therefore is that such a compact
self-ballasted fluorescent lamp may partially protrude from an
existing lighting fixture designed for an incandescent lamp. To
solve this problem, the inventors of the present application have
come up with the idea that the total height of compact
self-ballasted fluorescent lamps can be reduced by winding also the
end portions of the arc tube, which had conventionally been formed
to stand vertically, into a double spiral around the axis of
spiral. With this idea, the inventors have succeeded in downsizing
compact self-ballasted fluorescent lamps to substantially the same
size as incandescent lamps.
[0004] FIG. 1 shows a holding member for holding an arc tube whose
end portions are formed in a double spiral. As shown in the figure,
the holding member 906 is in a cylindrical shape whose one end is
closed, and has, on its closed end, i.e., on its bottom wall 961, a
pair of tubular parts in which a pair of insertion openings 963 and
964 are formed for allowing both ends of the arc tube to be
inserted therethrough. The holding member 906 holds the arc tube by
bonding the ends of the arc tube that have been inserted therein
through the insertion openings 963 and 964 to the inner surface of
the holding member 906 via a bonding agent.
[0005] Although compact self-ballasted fluorescent lamps including
the above-described arc tube whose end portions are formed in a
double spiral can have a low total height substantially the same as
that of incandescent lamps, a problem still remains as that
inserting the ends of the arc tube thorough the insertion openings
963 and 964 of the holding member 906 is extremely difficult. To be
more specific, the insertion of the ends of the arc tube is
extremely difficult because the insertion openings 963 and 964 are
provided in directions opposite to each other. Once one end of the
arc tube is inserted through the insertion opening 963, the other
end of the arc tube goes off from the insertion opening 964.
[0006] The insertion of the ends of the arc tube through the
insertion openings 963 and 964 can be made relatively easy by
enlarging the insertion openings 963 and 964. If the insertion
openings 963 and 964 are large, however, another problem arises
when the ends of the arc tube are bonded to the inner surface of
the holding member 906 via a bonding agent. The problem is that the
bonding member may flow out from the insertion openings 963 and
964, thereby leading to serious degradation of the appearance.
DISCLOSURE OF THE INVENTION
[0007] In view of the above problems, the object of the present
invention is to provide a low-pressure mercury lamp in which ends
of an arc tube can be easily inserted into a holding member without
for example enlarging the insertion openings, and also to provide a
method for assembling the low-pressure mercury lamp.
[0008] The above object of the present invention can be achieved by
a low-pressure mercury lamp, including: an arc tube whose at least
one end is wound around an axis entirely in a longitudinal
direction thereof; and a holding member that holds the arc tube in
a state where the at least one end is inserted in an opening formed
in the holding member, wherein the holding member includes an
insertion-guiding unit for guiding the at least one end of the arc
tube to be inserted into the opening while preventing positional
deviation of the at least one end, when the arc tube is rotated
around the axis to be attached to the holding member.
[0009] According to this construction, by rotating the arc tube
around the spiral axis with the end of the arc tube being in
contact with the insertion-guiding unit, the end of the arc tube
can be easily inserted into the opening formed in the holding
member. It should be noted here that the above longitudinal
direction is the direction in which the end of the arc tube is
wound around the axis, i.e., the spiral direction.
[0010] In particular, the insertion-guiding unit may be formed as a
groove extending in a direction in which the end of the arc tube is
wound around the axis.
[0011] Also, a part of the groove that comes in contact with a part
of the end of the arc tube may have a shape corresponding to a
shape of the part of the end of the arc tube.
[0012] According to this construction, the end of the arc tube can
be guided to be inserted into the opening of the holding member
while the positional deviation of the arc tube is being
prevented.
[0013] Further, the arc tube may include a pair of lead wires for
an electrode extending from the end of the arc tube, the opening
may open toward a direction of the axis, and the holding member may
allow the pair of lead wires to be inserted in the opening.
[0014] In particular, the opening may be formed at an angle of 20
to 60.degree. inclusive with respect to the axis.
[0015] According to this construction, by making the lead wires in
parallel with the spiral-axis direction of the arc tube and moving
the arc tube toward the holding member in the spiral-axis direction
before for example attaching the arc tube to the holding member,
the lead wires can be easily inserted into the holding member
through the opening.
[0016] Also, the holding member may include a covering unit that is
formed so that the opening is positioned at an edge of the covering
unit, the covering unit covering the end of the arc tube, and the
opening may be partially formed by a notch created in the covering
unit and/or the insertion-guiding unit.
[0017] According to this construction, by making the lead wires in
parallel with the spiral-axis direction of the arc tube and moving
the arc tube toward the holding member in the spiral-axis direction
before for example attaching the arc tube to the holding member,
the lead wires can be easily inserted into the holding member
through the notch.
[0018] On the other hand, the end of the arc tube may be bonded
within the holding member via a bonding agent.
[0019] Further, the insertion-guiding unit may include one or more
inlets for injecting the bonding agent in an area between (a) the
end of the arc tube placed in the holding member and (b) the
insertion-guiding unit of the holding member.
[0020] Alternatively, the holding member may include a wall at an
internal surface thereof for preventing the bonding agent from
flowing outside.
[0021] This construction ensures that the arc tube is firmly held
by the holding member.
[0022] Further, the arc tube may include a pair of lead wires for
an electrode extending from the end of the arc tube, and the
holding member may include a supporting unit for supporting the
pair of lead wires while keeping a certain distance between the
lead wires.
[0023] According to this construction, the lead wires are held with
a certain distance kept between them. Therefore, for example,
crossing or entangling of the lead wires can be reduced.
[0024] Further, the arc tube may include a glass tube that is
turned at a substantially middle thereof and wound around the axis
from the middle, to have a double-spiral structure.
[0025] According to this construction, the total height of the arc
tube can be made lower than an arc tube whose end portions are
parallel with the spiral axis.
[0026] The above object of the present invention can also be
achieved by a method for assembling a low-pressure mercury lamp
including: an arc tube whose at least one end is wound around an
axis entirely in a longitudinal direction thereof; and a holding
member that includes an insertion-guiding unit for guiding the at
least one end of the arc tube to be inserted into an opening formed
in the holding member while preventing positional deviation of the
at least one end, wherein a process of attaching the arc tube to
the holding member includes the steps of: making the at least one
end of the arc tube come in contact, at a peripheral surface
thereof, with the insertion-guiding unit of the holding member; and
rotating, in a state where the at least one end of the arc tube is
in contact with the insertion-guiding unit, the arc tube and/or the
holding member around the axis, so that the arc tube has a relative
position with respect to the opening of the holding member.
[0027] According to this method, the arc tube can be easily
attached to the holding member. Further, the end of the arc tube
can be easily inserted into the holding member by rotating the arc
tube with its end being in contact with the insertion-guiding unit
at a peripheral surface thereof. Therefore, automation of this
process becomes possible. It should be noted here that the above
longitudinal direction is the direction in which the end of the arc
tube is wound around the axis, i.e., the spiral direction.
[0028] Also, the arc tube may have a pair of lead wires for an
electrode extending from the end of the arc tube, the opening may
open toward a direction of the axis, and the step of making the at
least one end of the arc tube come in contact with the
insertion-guiding unit of the holding member may be carried out in
a state where the lead wires are parallel to the direction of the
axis.
[0029] According to this method, by making the arc tube come in
contact with the holding member with the tips of the lead wires and
the opening being at the same positions in the spiral-axis
direction, the lead wires can be easily inserted into the holding
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] These and other objects, advantages and features of the
invention will become apparent from the following description
thereof taken in conjunction with the accompanying drawings that
illustrate a specific embodiment of the invention. In the
drawings:
[0031] FIG. 1 is a perspective view of a holder according to a
conventional technique as viewed diagonally from above;
[0032] FIG. 2 is a front view showing the overall construction of a
compact self-ballasted fluorescent lamp according to a first
embodiment of the present invention, with its right half being cut
away;
[0033] FIG. 3 is a front view showing the construction of an arc
tube according to the first embodiment, with being partially cut
away;
[0034] FIG. 4 is a perspective view of a holder according to the
first embodiment as viewed diagonally from above;
[0035] FIG. 5 is a perspective view of the arc tube attached to the
holder according to the first embodiment as viewed diagonally from
above;
[0036] FIG. 6 is a perspective view of the arc tube attached to the
holder according to the first embodiment placed upside down, as
viewed diagonally from above;
[0037] FIGS. 7A to 7C are diagrams for explaining processes for
attaching the arc tube to the holder according to the first
embodiment;
[0038] FIG. 8 is a perspective view of a holder according to a
modification of the first embodiment;
[0039] FIG. 9 is a perspective view of a holder according to a
second embodiment of the present invention as viewed diagonally
from above;
[0040] FIGS. 10A and 10B are diagrams for explaining processes for
attaching the arc tube to the holder according to the second
embodiment;
[0041] FIG. 11 is a perspective view of a holder according to a
modification of the second embodiment;
[0042] FIG. 12 is a perspective view of a holder according to a
third embodiment of the present invention placed upside down, as
viewed diagonally from above;
[0043] FIG. 13 is a perspective view of a holder according to a
modification of the third embodiment;
[0044] FIG. 14 is a perspective view of a holder according to a
fourth embodiment of the present invention placed upside down, as
viewed diagonally from above;
[0045] FIG. 15 is a perspective view of a holder according to a
modification of the fourth embodiment; and
[0046] FIG. 16 is a front view of another fluorescent lamp to which
the present invention is applied.
BEST MODE FOR CARRYING OUT THE INVENTION
FIRST EMBODIMENT
1. Construction of the Compact Self-Ballasted Fluorescent Lamp
(1) Overall Construction
[0047] FIG. 2 is a front view showing the overall construction of a
compact self-ballasted fluorescent lamp according to a first
embodiment of the present invention, with its substantially half
being cut away. The compact self-ballasted fluorescent lamp 1 is a
12 W lamp that is an alternative to a 60 W incandescent lamp. It
should be noted here that a 60 W incandescent lamp has a maximum
outer diameter of 60 mm and a total height of 110 mm.
[0048] As shown in the figure, the compact self-ballasted
fluorescent lamp 1 includes an arc tube 2 that has a double-spiral
structure, an electronic ballast 3 for lighting the arc tube 2, and
a case 4 containing the electronic ballast 3 and having a base
5.
[0049] FIG. 3 is a front view showing the construction of the arc
tube 2 being partially cut away.
[0050] As shown in FIGS. 2 and 3, the arc tube 2 is formed by
bending one glass tube 9. To be more specific, the glass tube 9 is
turned at a turning portion 91 positioned substantially middle
thereof, and is wound around an axis of spiral "A" from the turning
portion 91 to its both ends 92 and 93 at an angle of spiral.
[0051] It should be noted here that the glass tube 9 is wound at a
spiral angle ".alpha." (75.degree. in the present embodiment) with
respect to the spiral axis "A" from a position of the turning
portion 91 until positions just before its end portions in the
vicinity of the ends 92 and 93, and is wound at a spiral angle
".beta." (about 68.degree. in the present embodiment) with respect
to the spiral axis "A" from positions at the start of the end
portions until positions of the ends 92 and 93. It should also be
noted here that in the present embodiment the end portions of the
glass tube each extend, as viewed from above, in a range of about
1/4 winds from the end of the glass tube in a direction where the
turning portion 91 is positioned.
[0052] The spiral angle of the glass tube 2 with respect to the
spiral axis "A" is changed in the vicinity of the ends 92 and 93,
for the purpose of making the ends 92 and 93 away from portions of
the glass tube 9 adjacent to the ends 92 and 93 in a direction
parallel to the spiral axis "A" (hereafter simply referred to as a
"spiral-axis direction"), and thereby allowing the arc tube 2 to be
easily held by a holder, which is described later.
[0053] Hereafter, the direction in which the glass tube 9 is wound
around the spiral axis "A" at the spiral angle (the direction in
which the glass tube 9 is wound from its turning portion to ends)
is referred to as the "spiral direction". For the compact
self-ballasted fluorescent lamp 1, the side where the tuning
portion 91 of the arc tube 2 is positioned is assumed to be the
"upper side", and the side where the base 5 is positioned is
assumed to be the "lower side".
[0054] The glass tube 9 has a tube inner diameter of 7.4 mm, a tube
outer diameter of 9.0 mm. A gap between every adjacent portions of
the glass tube 9 in the spiral-axis direction, excluding the end
portions, is about 1 mm, and a gap between the ends 92 and 93 and
adjacent portions of the glass tube 9 is about 6 mm at the maximum.
The glass tube 9 is wound from the turning portion 91 to the ends
92 and 93 around the spiral axis "A" by substantially 4.5 winds.
The arc tube 2 with a double-spiral structure has a total height of
60 mm and a maximum outer diameter of 37 mm.
[0055] As shown in FIG. 3, an electrode 8 is sealed at the end 93
of the glass tube 9. As one example, a coil electrode made of
tungsten is used as the electrode 8. The coil electrode is
supported by a pair of lead wires 8a and 8b temporarily fixed via
bead glass 82 (by way of a "bead glass mounting method").
[0056] Although not shown in the figure, an electrode is also
sealed at the end 92 of the glass tube 9. In the figure, a pair of
lead wires 7a and 7b connected to the coil electrode (not shown)
extends from the end 92.
[0057] As shown in FIG. 3, an exhaust tube 85 for exhausting the
inside of the glass tube 9 is sealed at one end (the end 93 in this
example) of the glass tube 9 at the time when the electrode 8 is
sealed there. It should be noted here that the distance between the
electrodes within the glass tube 9 is 400 mm.
[0058] Here, a rare-earth phosphor 95 is applied to the inner
surface of the glass tube 9. The phosphor 95 used here is a mixture
of three types of phosphors respectively emitting red, green, and
blue light, e.g., Y.sub.2O.sub.3:Eu, LaPO.sub.4:Ce, Tb, and
BaMg.sub.2Al.sub.16O.sub.27:Eu, Mn.
[0059] Within the glass tube 9, mercury is singly enclosed by an
amount of about 5 mg, and also, a rare gas such as a mixture gas of
argon and neon (with a capacity ratio of neon in the mixture gas
being substantially 25%) is enclosed at 400 Pa via the exhaust tube
85.
[0060] Here, the finished structure of the glass tube 9 in which
the phosphor layer 95 has been applied to the inner surface, the
rare gas has been enclosed inside, etc., corresponds to the arc
tube 2. Hereafter, an explanation given using the arc tube 2
assumes that both ends of the arc tube 2 corresponding to the ends
92 and 93 of the glass tube 9 are referred to as "ends 92 and 93 of
the arc tube 2", a portion of the glass tube 9 in the vicinity of
its end 92 is referred to as an "end portion 92a of the arc tube
2", and a portion of the glass tube 9 in the vicinity of its end 93
is referred to as an "end portion 93a of the arc tube 2". It should
be noted here that the end portions 92a and 93a of the arc tube 2
correspond to the "end that is wound around the axis entirely in
the longitudinal direction" referred to in the claims of the
present invention.
[0061] As shown in FIG. 2, the ends 92 and 93 of the arc tube 2 are
inserted into a holder 6 and bonded to the holder 6 via such a
bonding agent as silicone (not shown). The holder 6 is described in
detail later.
[0062] As shown in FIG. 2, a substrate 31 is attached at the
backside of the holder 6 (at the side where the base 5 is
positioned). A plurality of electronic components 32, 33, etc. for
lighting the arc tube 2 are mounted on the substrate 31. It should
be noted here that these electronic components 32, 33, etc.
constitute the electronic ballast 3.
[0063] The case 4 is made of a synthetic resin and is in a tubular
shape having a larger diameter as closer to its top. The holder 6
to which the arc tube 2 and the substrate 31 are attached is placed
in the opening of the case 4 from the side (lower side) where the
electronic ballast 3 is positioned and is fixed therein. The base 5
(e.g., an E26 type base) is attached to the bottom end of the case
4, i.e., the side of the case 4 opposite to the opening. It should
be noted here that electrical connection between the base 5 and the
electronic ballast 3 is not shown in FIG. 2.
[0064] The base 5 is of a screw type, with its central axis being
substantially matching the spiral axis "A" of the arc tube 2.
Hereafter, the central axis of the base 5 may also be referred to
as the "central axis of the compact self-ballasted fluorescent lamp
1".
(2) Construction of the Holder
[0065] FIG. 4 is a perspective view of the holder 6 as viewed
diagonally from above. FIG. 5 is a perspective view of the holder 6
to which the arc tube 2 is attached, as viewed diagonally from
above. FIG. 6 is a perspective view of the holder 6 to which the
arc tube 2 is attached as viewed diagonally from below.
[0066] As shown in FIGS. 4 to 6, the holder 6 is in a cylindrical
shape whose one end is closed. The holder 6 has a bottom wall 61
and a peripheral wall 62. The holder 6 has two insertion openings
63 and 64 at the bottom wall 61. The insertion openings 63 and 64
are for allowing the ends 92 and 93 of the arc tube 2 to be
inserted therethrough. As shown in FIG. 6, the ends 92 and 93 of
the arc tube 2 that have been inserted through the insertion
openings 63 and 64 of the holder 6 are bonded via a bonding agent
65 such as silicone. In this way, the arc tube 2 is held by the
holder 6.
[0067] Here, in the front view of the insertion openings 63 and 64
viewed in the direction where the ends 92 and 93 are moved (a track
to be drawn by the ends 92 and 93) when the ends 92 and 93 of the
arc tube 2 are inserted into the holder 6 through the insertion
openings 63 and 64, an "area in short of the insertion opening in
the direction where the ends 92 and 93 are moved" is assumed to be
an "area-before the insertion opening", and an "area beyond the
insertion opening in the direction where the ends 92 and 93 are
moved" is assumed to be an "area after the insertion opening".
[0068] It should be noted here that the bottom wall 61 is
substantially perpendicular to a central axis "B" of the peripheral
wall 62 (hereafter referred to as the "central axis "B" of the
holder 6"), in such a manner that a center "O2" of the bottom wall
61 is positioned on the central axis "B" of the holder 6. Also, the
arc tube 2 is held by the holder 6 with the spiral axis "A" of the
arc tube 2 substantially matching the central axis "B" of the
holder 6.
[0069] As shown in FIG. 4, the insertion openings 63 and 64 are in
a circular shape corresponding to the outer shape of the ends 92
and 93, so as to allow the ends 92 and 93 to be inserted
therethrough. The insertion openings 63 and 64 are formed on a
plane perpendicular to the bottom wall 61.
[0070] The centers "O3" and "O4" of the insertion openings 63 and
64 are positioned on a track "X" to be drawn on a plane by the
centers of cross sections of the ends 92 and 93 of the arc tube 2
when the arc tube 2 is rotated in the spiral direction (to right in
FIG. 4) with the spiral axis "A" of the arc tube 2 matching the
central axis "B" of the holder 6.
[0071] To be more specific, a distance between the centers "O3" and
"O4" of the insertion openings 63 and 64 via the central axis "B"
of the holder 6 (a distance "D.sub.2" in FIG. 4) is equal to a
diameter of the arc tube 2 formed by the glass tube 9 being wound
around the spiral axis "A" (a diameter "D.sub.1" in FIG. 3).
[0072] The centers "O3" and "O4" of the insertion openings 63 and
64 are positioned at substantially the middle of the bottom wall 61
in its thickness direction, on a plane parallel to the surface of
the bottom wall 61. Each of the insertion openings 63 and 64 is
formed in such a manner that an upper half of its periphery
protrudes in a semi-circular shape from the bottom wall 61 and a
lower half of its periphery recesses in a semi-circular shape from
the bottom wall 61.
[0073] In areas before the insertion openings 63 and 64, guide
grooves 66 and 67 are formed. The guide grooves 66 and 67 are
provided for guiding the ends 92 and 93 of the arc tube 2 toward
the insertion openings 63 and 64 while preventing deviation of the
ends 92 and 93 of the arc tube 2. To insert the ends 92 and 93 of
the arc tube 2 into the holder 6, the end portions 92a and 93a are
first placed to come in contact with the guide grooves 66 and 67.
In this state, the arc tube 2 is then rotated around the spiral
axis "A" in the spiral direction, so that the ends 92 and 93 of the
arc tube 2 are guided to the insertion openings 63 and 64 by the
guide grooves 66 and 67. It should be noted here that the guide
grooves 66 and 67 correspond to the "insertion-guiding unit"
referred to in the claims of the present invention.
[0074] The guide grooves 66 and 67 are formed in the spiral
direction, in correspondence with the outer shape of the end
portions 92a and 93a that have been wound in a double spiral. The
guide grooves 66 and 67 are continuous to the lower halves of the
peripheries of the insertion openings 63 and 64. To be more
specific, the guide grooves 66 and 67 have the same semi-circular
cross sections as the semi-circular cross sections of the lower
parts of the end portions 92a and 93a of the arc tube 2, and allow
the lower parts of the end portions 92a and 93a of the arc tube 2
to come in contact. It should be noted here that the surfaces of
the guide grooves 66 and 67 with which the end portions 92a and 93b
come in contact are referred to as the "contact surfaces 66a and
67a". The guide grooves 66 and 67 are formed deeper as they are
closer to the insertion openings 63 and 64.
[0075] To be more specific, the guide grooves 66 and 67 have the
contact surfaces 66a and 67a being wound in the same manner as that
for the end portions 92a and 93a of the arc tube 2, i.e., wound
around the central axis "B" of the holder 6 at the spiral angle
".beta.".
[0076] On the other hand, in areas after the insertion openings 63
and 64, covering units 68 and 69 are formed. The covering units 68
and 69 are provided for covering the ends 92 and 93 and the end
portions 92a and 93a of the arc tube 2 inserted in the holder 6. As
shown in FIG. 4, the covering units 68 and 69 are continuous from
the upper halves of the peripheries of the insertion openings 63
and 64, and extend in the spiral direction of the end portions 92a
and 93a of the arc tube 2. The covering units 68 and 69 and are
each formed in the shape of an arch.
[0077] To be more specific, the covering units 68 and 69 have the
semi-circular cross sections corresponding to the semi-circular
cross sections of the upper parts of the end portions 92a and 93a
of the arc tube 2, and allow the upper parts of the end portions
92a and 93a of the arc tube 2 to be fit therein. The arches of the
covering units 68 and 69 are formed lower as they are less closer
to the insertion openings 63 and 64.
2. Processes for Assembling Compact Self-Ballasted Fluorescent
Lamp
[0078] The following describes processes for assembling the compact
self-ballasted fluorescent lamp 1 with the above-described
construction, in particular, the processes for attaching the arc
tube 2 to the holder 6. FIGS. 7A to 7C are diagrams for explaining
the processes for inserting the arc tube 2 into the holder 6
through the insertion openings 63 and 64.
[0079] First, the arc tube 2 with a double-spiral structure and the
holder 6 for holding the arc tube 2 are prepared. The arc tube 2
and the holder 6 are aligned so that the spiral axis "A" of the arc
tube 2 substantially matches the central axis "B" of the holder 6,
and the ends 92 and 93 of the arc tube 2 are positioned above the
insertion openings 63 and 64 in the direction of the central axis
"B". The arc tube 2 is then moved toward the holder 6 along the
central axis "B" of the holder 6 in the direction indicated by an
arrow shown in FIG. 7A, and the arc tube 2 is placed on the holder
6 in such a manner that the end portions 92a and 93a are fit in the
guide grooves 66 and 67.
[0080] Here, the lower parts of the end portions 92a and 93a of the
arc tube 2 are in contact with the contact surfaces 66a and 67a of
the guide grooves 66 and 67. Because the guide grooves 66 and 67
are formed to have the contact surfaces 66a and 67a along the lower
parts of the end portions 92a and 93a of the arc tube 2, the arc
tube 2 can be placed stably on the holder 6.
[0081] Also, the guide groove 66 (or 67) is provided in an area
before the insertion opening 63 (or 64) so as to extend in a wide
range "C" (see FIG. 4) from the insertion opening 63 (or 64) to a
position of about 1/5 of one wind around the central axis "B" of
the holder 6. Therefore, the end portions 92a and 93a of the arc
tube 2 can be easily placed on the guide grooves 66 and 67.
[0082] Next, the arc tube 2 placed on the holder 6 is rotated
around the spiral axis "A" in the spiral direction indicated by an
arrow in FIG. 7B, so that the ends 92 and 93 of the arc tube 2 are
moved toward the insertion openings 63 and 64 along the guide
grooves 66 and 67. As shown in FIG. 7C, the ends 92 and 93 of the
arc tube 2 are finally inserted into the holder 6 through the
insertion openings 63 and 64.
[0083] Here, the guide grooves 66 and 67 are formed as continuous
to the insertion openings 63 and 64 in the spiral direction of the
end portions 92a and 93a of the arc tube 2. By such guide grooves
66 and 67, the ends 92 and 93 of the arc tube 2 are guided to the
insertion openings 63 and 64 and smoothly inserted into the holder
6 through the insertion openings 63 and 64, simply by rotating the
arc tube 2 around the spiral axis "A" matching the central axis "B"
of the holder 6. During the insertion, the positional deviation of
the arc tube 2 placed on the guide grooves 66 and 67 is also
prevented. In this way, the conventional problem of difficulties in
inserting ends of an arc tube into the insertion openings 963 and
964 of the holder 906 can be solved.
[0084] As described above, the ends 92 and 93 of the arc tube 2 can
be inserted into the holder 6 through the insertion openings 63 and
64 simply by rotating the arc tube 2 around the spiral axis "A"
after placing the end portions 92a and 93a of the arc tube 2 on the
guide grooves 66 and 67 of the holder 6. Therefore, automation of
this process becomes possible.
[0085] Further, in the compact self-ballasted fluorescent lamp 1 in
which the arc tube 2 is attached to the holder 6 with the
above-described construction, the end portions 92a and 93a of the
arc tube 2 are covered by the covering units 68 and 69. This means
that electrodes and the like sealed at the ends 92 and 93 of the
arc tube 2 can also be covered up.
3. Others
i) Covering Unit
[0086] Although the first embodiment describes the case where the
covering units 68 and 69 are formed in the areas after the
insertion openings 63 and 64 of the holder 6, the covering units 68
and 69 may not necessarily be provided. This is because easy
insertion of the arc tube 2 into the holder 6 through the insertion
openings 63 and 64 only requires the guide grooves 66 and 67 formed
in the areas before the insertion openings 63 and 64.
[0087] FIG. 8 is a perspective view of a holder in which covering
units are not provided.
[0088] As shown in the figure, the holder 106 has, at its bottom
wall 161, insertion openings 163 and 164 and guide grooves 166 and
167. The guide grooves 166 and 167 have the same constructions as
the guide grooves 66 and 67 described in the first embodiment. The
insertion openings 163 and 164 are composed of openings formed in
the bottom wall 161 by removing the covering units 68 and 69
described in the first embodiment and openings corresponding to the
insertion openings 63 and 64 described in the first embodiment
formed at the edges of the guide grooves 66 and 67.
[0089] The holder 106 does not have covering units (68 and 69), and
therefore can have the bottom wall 161 being flat without any
recession and protrusion. Such a flat bottom wall can represent an
improvement in the design. In this case where the covering units
are not provided, however, the end portions 92a and 93a of the arc
tube 2 need to be inserted into the holder 106 to such a degree
that enables electrodes sealed at the ends 92 and 93 to be covered
up.
ii) Guide Groove
(Shape of Cross Section)
[0090] The first embodiment describes the case where the guide
grooves 66 and 67 have the contact surfaces 66a and 67a with which
the lower parts of the end portions 92a and 93a of the arc tube 2
come in contact, and such guide grooves 66 and 67 prevent the
positional deviation of the arc tube 2 in a direction perpendicular
to the spiral axis "A" (horizontal direction) when the arc tube 2
is rotated for its attachment. However, the lower parts of the end
portions 92a and 93a of the arc tube 2 may not necessarily come in
contact with substantially the entire guide grooves 66 and 67, as
long as the guide grooves 66 and 67 can prevent the positional
deviation of the arc tube 2 in the direction perpendicular to the
spiral axis "A" when the arc tube 2 is rotated.
[0091] For example, the guide grooves 66 and 67 may be formed to
have a cross section in a rectangular shape or a V-shape. The guide
grooves 66 and 67 may further be formed to have a semi-circular
cross section that is partially the same as the semi-circular cross
section of the lower parts of the end portions 92a and 93a of the
arc tube 2. The guide grooves 66 and 67 having cross sections of
any of the above shapes can also guide the ends 92 and 93 of the
arc tube 2 to the insertion openings 63 and 64.
(Shape of Vertical Section)
[0092] The first embodiment describes the case where the guide
grooves 66 and 67 have the contact surfaces 66a and 67a that are
continuous in the spiral direction along the end portions 92a and
93a of the arc tube 2, so that the guide grooves 66 and 67 can
guide, without deviation, the ends 92 and 93 of the arc tube 2
toward the insertion openings 63 and 64 in the spiral direction
when the arc tube 2 is rotated around the spiral axis "A".
[0093] However, the guide grooves 66 and 67 do not need to have the
contact surfaces 66a and 67a that are continuous in the spiral
direction, as long as the guide grooves 66 and 67 enable the arc
tube 2 before being inserted into the holder 6 to be placed thereon
in a stable manner and can guide without deviation the ends 92 and
93 toward the insertion openings 63 and 64 in the spiral direction
when the arc tube 2 is rotated around the spiral axis "A".
[0094] As one example, the guide grooves 66 and 67 may have
discontinuous contact surfaces with which the end portions 92a and
93a of the arc tube 2 before being inserted into the holder 6 come
in contact at two or more positions thereof in the spiral
direction. In this case, the end portions 92a and 93a of the arc
tube 2 need to keep in contact with the contact surfaces at two or
more positions thereof while the arc tube 2 is being rotated.
[0095] As a specific example of such, the guide grooves 66 and 67
may be provided with contact parts arranged at certain intervals
for allowing the end portions 92a and 93a of the arc tube 2 to come
in contact. In this case, too, the same effects as produced by the
continuous contact surfaces 66a and 67a described above can be
produced.
iii) Insertion Opening
[0096] The first embodiment describes the case where the insertion
openings 63 and 64 formed at the bottom wall 61 of the holder 6 are
in such a circular shape corresponding to the outer shape of the
ends 92 and 93 of the arc tube 2. In the case of the arc tube 2
whose ends have an outer shape different from the shape described
in the first embodiment, it is preferable to form the insertion
openings 63 and 64 in such a shape determined accordingly.
[0097] However, the shape of the insertion openings 63 and 64 may
not necessarily be the same as the outer shape of the ends 92 and
93 of the arc tube 2, as long as the insertion openings 63 and 64
allow the ends 92 and 93 of the arc tube 2 to be inserted
therethrough into the holder 6.
[0098] One specific example is a case where the outer shape of the
ends 92 and 93 and the end portions 92a and 93a of the arc tube 2
is circular and the shape of the insertion openings is
substantially square with its one side being a diameter of the
circular outer shape of the ends 92 and 93 and the end portions 92a
and 93a of the arc tube 2.
[0099] In this case, however, gaps larger than necessary are formed
between the corners of the insertion openings and the end portions
92a and 93a of the arc tube 2 inserted therethrough. The bonding
agent 65 may flow through these gaps when the ends 92 and 93 of the
arc tube 2 are bonded to the holder 6.
[0100] Also, although a plane on which the insertion openings 63
and 64 are provided is perpendicular to the bottom wall 61 and
includes the central axis "B" thereon, the plane where the
insertion openings 63 and 64 are provided may not necessarily
include the central axis "B" thereon. As one example, the plane
where the insertion openings 63 and 64 are provided may be a plane
forming a predetermined angle with respect to the radius direction
of the bottom wall 61.
[0101] Further, although the first embodiment describes the case
where the centers of the insertion openings 63 and 64 are
positioned at substantially the middle of the bottom wall 61 in its
thickness direction, on a plane substantially parallel to the
surface of the bottom wall 61, the positions of the centers of the
insertion openings 63 and 64 in the direction of the central axis
"B" may not necessarily be the same as the position of the bottom
wall 61, as long as the guide grooves 66 and 67 are provided to
extend toward the insertion openings 63 and 64 in the spiral
direction of the end portions 92a and 93a of the arc tube 2. For
example, the insertion openings 63 and 64 may entirely protrude
from the bottom wall 61, or may be entirely embedded below the
bottom wall 61.
SECOND EMBODIMENT
[0102] The inventors of the present application examined the
construction of the holder 6 that enables the ends 92 and 93 of the
arc tube 2 to be easily inserted into the holder 6, and the method
for attaching the arc tube 2 to the holder 6. As a result, the
inventors discovered that the holder 6 in which the guide grooves
66 and 67 are provided in the areas before the insertion openings
63 and 64 enable the ends 92 and 93 of the arc tube 2 to be easily
inserted into the holder 6 as described in the first
embodiment.
[0103] However, the inventors found difficulties in attaching the
arc tube 2 to the holder 6 described in the first embodiment, when
the arc tube 2 has lead wires 7a, 7b, 8a, and 8b that are for
supporting coil electrodes and extend from the ends 92 and 93. To
be specific, the inventors found difficulties in inserting the lead
wires 7a, 7b, 8a, and 8b smoothly through the insertion openings 63
and 64 of the holder 6.
[0104] The inventors then made preliminarily examinations on the
construction of a holder that enables ends of an arc tube from
which lead wires for electrodes extend, to be easily inserted into
the holder, and also on the method for attaching the arc tube to
the holder. As a result, the inventors discovered that the lead
wires are inserted relatively easily through the insertion openings
by bending the lead wires in a direction parallel to the
spiral-axis direction and inserting them through the insertion
openings in the spiral-axis direction.
1. Construction of the Holder
[0105] FIG. 9 is a perspective view of a holder that enables lead
wires for electrodes to be inserted easily into the holder. This
holder 206 results from the preliminary examinations described
above. The holder 206 is characterized in that its insertion
openings 263 and 264 are formed so as to provide openings as viewed
from above, for enabling the lead wires 207a, 207b, 208a, and 208b
(see FIG. 10) substantially parallel to the central axis "B" of the
holder 206, to be easily inserted therethrough when the arc tube
202 is attached to the holder 206.
[0106] The insertion openings 263 and 264 of the holder 206 are
inclined so that their upper parts are shifted in the direction
where the covering units 268 and 269 are provided. To be specific,
the insertion openings 263 and 264 are formed in such a manner that
a plane where the insertion opening is provided is inclined at an
angel ".gamma.", e.g., 40.degree. with respect to the central axis
"B" of the holder 206 as shown in FIG. 9. As viewed from above in
the direction of the central axis "B" in FIG. 9, the insertion
openings 263 and 264 are formed to provide openings between the
covering units 268 and 269 and the guide grooves 266 and 267.
2. Attachment Processes
[0107] FIGS. 10A and 10B are diagrams for explaining processes for
attaching an arc tube having lead wires for electrodes, to a
holder. First, the lead wires 207a, 207b, 208a, and 208b indicated
by bold lines in FIG. 10A extending from the ends 293 (and 294) of
the arc tube 202 are bent to the side opposite to the turning
portion 91 in a direction parallel to the spiral-axis direction
("A" in the figure) of the arc tube 202, at positions close to the
ends 293 (and 294) of the arc tube 202. The lead wires 207a, 207b,
208a, and 208b after being bent are indicated by interrupted lines
in FIG. 10A.
[0108] Following this, the arc tube 202 and the holder 206 are
aligned so that the spiral axis "A" of the arc tube 202
substantially matches the central axis "B" of the holder 206, and
that the lead wires 207a, 207b, 208a, and 208b are positioned to
enter in the openings formed between the covering units 268 and 269
and the guide grooves 266 and 267 of the holder 206 as viewed from
above. Then, the arc tube 202 is moved toward the holder 206 in the
direction indicated by an arrow in FIG. 10B, i.e., in the direction
of the spiral axis "A". Here, the arc tube 202 is moved while its
aligned position in a direction perpendicular to the spiral axis
"A" is being maintained.
[0109] Here, the insertion openings 263 and 264 of the holder 206
are inclined with respect to the spiral axis "A" of the arc tube
202 (the central axis "B" of the holder 206). As viewed from above,
therefore, the insertion openings 263 and 264 provide the openings
formed between the covering units 268 and 269 and the guide grooves
266 and 267. The lead wires 207a, 207b, 208a, and 208b bent to be
substantially parallel to the spiral axis "A" can be easily
inserted into the holder 206 through such openings formed between
the covering units 268 and 269 and the guide grooves 266 and 267 as
shown in FIG. 10B.
[0110] The arc tube 202 is further moved toward the holder 206, so
that the end portions 293a (and 294a) of the arc tube 202 are fit
in the guide grooves 266 and 267 of the holder 206. The subsequent
processes are the same as the processes described in the first
embodiment.
3. Others
i) Inclination of Insertion Opening
[0111] Although the second embodiment describes the case where the
insertion openings 263 and 264 are inclined at an angle of
40.degree. (".beta." in the figure) with respect to the central
axis "B" of the holder 206 as show in FIG. 9, the angle of
inclination ".gamma." should not be limited to 40.degree.. The
angle of inclination ".gamma." may be set at any value smaller than
90.degree.. However, it is preferable that the angle ".lamda." is
in a range of 20 to 60.degree. inclusive.
[0112] This range is determined due to the following reason. When
the angel ".lamda." is smaller than 20.degree., the openings formed
between the covering units 268 and 269 and the guide grooves 266
and 267 are so small that inserting the lead wires 207a, 207b,
208a, and 208b into the holder 206 through the openings becomes
difficult.
[0113] On the other hand, when the angel ".lamda." is larger than
60.degree. the bonding agent used for bonding the ends 293 and 294
of the arc tube 202 to the holder 206 may flow through the
insertion openings 263 and 264.
[0114] Also, although the second embodiment describes the case
where the insertion openings 263 and 264 are formed in such a
manner that the upper halves thereof (the peripheries of the ends
of the covering units 268 and 269) and the lower halves thereof
(the peripheries of the ends of the guide grooves 266 and 267) are
inclined at the same angles with respect to the central axis "B" of
the holder 206, only the upper halves or the lower halves of the
insertion openings 263 and 264 may be inclined with respect to the
central axis "B" of the holder 206, or the upper halves and the
lower halves of the insertion openings 263 and 264 may be inclined
at different angles with respect to the central axis "B" of the
holder 206.
ii) Modification of the Second Embodiment
[0115] The second embodiment describes the case where the insertion
openings 263 and 264 are inclined so as to provide openings between
the covering units 268 and 269 and the guide grooves 266 and 267 as
viewed from above, for the purpose of enabling the lead wires 207a,
207b, 208a, and 208b to be easily inserted into the holder 206
through the insertion openings 263 and 264. However, the covering
units 268 and 269 and the guide grooves 266 and 267 may have other
constructions to provide openings between them.
[0116] FIG. 11 is a perspective view of a holder having notches
formed in the vicinity of its insertion openings. As shown in the
figure, the holder 206 has notches 270a, 270b, 271a, and 271b
formed in the covering units 268 and 269 and the guide groves 266
and 267, so as to widen the insertion openings 263 and 264 as
viewed from above in the direction of the central axis "B". In the
case of this holder 206 as in the second embodiment, the lead wires
207a, 207b, 208a, and 208b extending from the ends 293 and 294 of
the arc tube 202 can be easily inserted into the holder 206 by
bending the lead wires 207a, 207b, 208a, and 208b in parallel with
the spiral axis "A" of the arc tube 202.
[0117] Also, although the present modification describes the case
where the notches 270a and 271a are formed in the covering units
268 and 269 and the notches 270b and 271b are formed in the guide
grooves 266 and 267, notches may be formed only in the covering
units 268 and 269 or in the guide grooves 266 and 267. In either
case, however, the total area of the notches formed is to be
substantially the same as the total area of the notches 270a, 270b,
271a, and 271b formed in the covering units 268 and 269 and the
guide grooves 266 and 267, so that the lead wires 207a, 207b, 208a,
and 208b can be easily inserted into the holder 206.
[0118] Although the notches 270a, 270b, 271a, and 271b are each
formed to have substantially a semi-circular shape as viewed from
above in the direction of the central axis "B" in FIG. 11, the
notches 270a, 270b, 271a, and 271b may be each formed to have
another shape such as a V-shape and a rectangular shape as viewed
from above.
[0119] Further, slits may be formed instead of the notches 270a,
270b, 271a, and 271b. In this case, too, the same effects as
produced by the notches 270a, 270b, 271a, and 271b can be produced,
although inserting the lead wires 207a, 207b, 208a, and 208b
therethrough becomes more difficult in the case where the slits are
provided.
[0120] Also, the above examples and the second embodiment may be
combined. For example, the insertion openings 263 and 264 may be
formed in such a manner that the upper halves of their peripherals
are inclined with respect to the central axis "B" of the holder
206, and the notches 270b and 271b are formed in the guide grooves
266 and 267.
THIRD EMBODIMENT
[0121] The inventors of the present application examined the
construction of the holder that enables the ends of the arc tube to
be easily inserted therein and the method for attaching the arc
tube to the holder (first embodiment), and the construction of the
holder 206 that enables the lead wires 207a, 207b, 208a, and 208b
extending from the ends 293 and 294 of the arc tube 202 to be
smoothly inserted therein and the method for attaching the arc tube
202 to the holder 206 (second embodiment).
[0122] As a result, the inventors came up with the idea to provide
the guide grooves 66 and 67 in the areas before the insertion
openings 63 and 64 of the holder 6, and the idea to widen the
insertion openings 263 and 264 as viewed from above, as descried in
the first and second embodiments.
[0123] However, the inventors are encountered with a new problem
that the bonding agent cannot be injected by a sufficient amount
between (a) the holder 206 and (b) the ends and the end portions of
the arc tube 202, when the ends of the arc tube 202 inserted in the
holder 206 are bonded to the holder 206 via the bonding agent.
[0124] FIG. 12 is a perspective view of a holder that enables the
bonding agent to be injected by a sufficient amount in an area
where the arc tube and the holder are bonded together. As shown in
the figure, the holder 306 in the present embodiment has a
plurality of, e.g, three, inlets 380 at bottoms 366a and 367a of
the guide grooves 366 and 367. The inlets 380 are provided for
injecting the bonding agent between the end portions of the arc
tube and the surfaces (with which the arc tube comes in contact) of
the guide grooves 366 and 367.
[0125] It should be noted here that because the holder 306 is
placed upside down in FIG. 12, the guide grooves 366 and 367 are
each viewed in the shape of an arch, and also that the inlets
formed in the guide groove 367 are not shown in the figure as
hidden by a peripheral wall 362.
[0126] This construction ensures that the bonding agent is injected
by a sufficient amount between the surfaces of the guide grooves
366 and 367 and the end portions of the arc tube in contact
therewith or opposed thereto, through the inlets 380 formed in the
bottoms 366a and 367a of the guide grooves 366 and 367. This
construction ensures that the arc tube and the surfaces of the
guide grooves 366 and 367 are bonded firmly together.
[0127] Because the three inlets 380 are arranged in the spiral
direction of the end portions of the arc tube in the bottoms 366a
and 367a of the guide grooves 366 and 367 of the holder 306, the
bonding agent can be filled substantially uniformly in an area
where the end portions of the arc tube are in contact with or
opposed to the guide grooves 366 and 367.
[0128] With this construction, an amount of bonding agent to be
injected can be optimized. Further, because the inlets 380 are
provided in the bottoms 366a and 367a of the guide grooves 366 and
367, the inlets 380 cannot be viewed from outside the holder 306
after the arc tube is bonded to the holder 306. Therefore, the
inlets 380 do not cause deterioration in the design.
[0129] FIG. 13 is a perspective view of a holder that can also
solve the above-described problem. This holder 306 includes
enclosure walls 381 and 382 to prevent flowing out of the bonding
agent injected in the vicinity of the ends of the arc tube. These
enclosure walls 381 and 382 are formed on the back surface of the
bottom wall 361 so as to enclose the ends and the end portions of
the arc tube inserted in the holder 306.
[0130] This construction prevents the bonding agent injected in the
vicinity of the ends of the arc tube from flowing toward the center
of the back surface of the bottom wall 361, thereby ensuring that
the bonding agent blocked in the enclosure walls 381 and 382 firmly
bonds the ends and the end portions of the arc tube to the holder
306.
[0131] Also, because the enclosure walls 381 and 382 are formed
along the ends and the end portions of the arc tube, the arc tube
and the enclosure walls 381 and 382 are bonded together via the
bonding agent. This enables the arc tube and the holder 306 to be
bonded firmly.
[0132] It should be noted here that the enclosure walls 381 and 382
come in contact with the arc tube when the ends of the arc tube are
inserted in the holder 306. The enclosure walls 381 and 382
therefore also have the function of blocking the insertion of the
arc tube. Accordingly, the enclosure walls 381 and 382 enable the
arc tube to be inserted into the holder 306 by substantially a
uniform distance. Therefore, the enclosure walls 381 and 382 can
function as walls to block the insertion of the arc tube even in a
case where the bonding agent is not injected in an area enclosed by
the enclosure walls 381 and 382.
FOURTH EMBODIMENT
[0133] The inventors of the present application succeeded in easily
attaching the arc tube to the holder and bonding the arc tube and
the holder firmly together, by utilizing the holders 6, 206, and
306 described in the first to third embodiments.
[0134] However, the inventors were encountered with a new problem
when attaching the substrate on which the electronic ballast is
mounted to the holder, and connecting the lead wires that extend
from the ends of the arc tube to the surface of the substrate where
the base is provided. The problem is that the lead wires are
crossed or entangled within the holder.
[0135] The inventors solved the above problem by providing the
holder with supporting units for supporting the lead wires. The
following describes the construction of the supporting units.
[0136] FIG. 14 is a perspective view of a holder having such
supporting units. As shown in the figure, this holder 406 has
supporting units 491 and 492 for supporting lead wires, at the back
surface of the bottom wall 461 in the vicinity of the ends of the
arc tube inserted in the holder 406.
[0137] The supporting unit 491 (or 492) is made up of a supporting
base 491a (or 492a) provided at the back surface of the bottom wall
461, and a pair of supporting slits-491b (or 492b) formed in the
supporting base 491a (or 492a) for supporting a pair of lead
wires.
[0138] It should be noted here that the pair of supporting slits
491b (or 492b) formed in the supporting base 491a (or 492a) are
positioned at a predetermined interval, to support a pair of lead
wires with a certain distance being kept between the lead
wires.
[0139] When the substrate is attached to this holder 406, pairs of
lead wires extending from the ends of the arc tube fixed to the
holder 406 are first set in the supporting slits 491b and 492b of
the supporting units 491 and 492, in such a manner that the lead
wires are not crossed or entangled within the holder 6.
[0140] The lead wires supported at the supporting slits 491b and
492b are then lead outside of the holder 406, in such a manner that
the lead wires are not crossed or entangled within the holder 6.
After this, the substrate on which the electronic ballast is
mounted is attached, for example, to the peripheral wall 462 of the
holder 406.
[0141] This construction prevents the lead wires from being
entangled. Also, because the pairs of lead wires extending from the
ends of the arc tube are supported at the supporting slits 491b and
492b with a certain distance being kept between the lead wires in
each pair, the lead wires do not come in contact with each other
(i.e. the lead wires are not short-circuited).
[0142] It should be noted here that the supporting units 491 and
492 may not necessarily be formed at the back surface of the bottom
wall 461 of the holder 406 but may be formed at other positions. As
one example, the supporting units 491 and 492 may be formed
directly in the peripheral wall 462 of the holder 406 as that is
shown in FIG. 15. In this case, two supporting units 495 and 496
are respectively made up of a pair of supporting slits 495a and a
pair of supporting slits 496a formed in the peripheral wall 462.
The supporting slits 495a and the supporting slits 496a are
positioned away from each other, e.g., positioned as opposed to
each other with respect to the central axis of the holder 406.
(Modifications)
[0143] Although the present invention is described based upon the
above embodiments, the contents of the present invention should not
be limited to specific examples shown in the above embodiments. For
example, the following modifications are possible.
1. Holding Member
[0144] Although the above embodiments describe the case where the
holding member is made up of a bottom wall and a peripheral wall
that are connected together, the holding member may be made up of
only a bottom wall. In this case, too, the provision of insertion
openings, insertion-guiding units, covering units etc. formed at
the bottom wall of the holding member can produce the same effects
as produced in the above embodiments.
[0145] Although the above embodiments describe the case where the
arc tube is held by the holding member (holder) with the spiral
axis of the arc tube matching the central axis of the holding
member, the arc tube may be held by the holding member with the
spiral axis of the arc tube being inclined with respect to the
central axis of the holding member.
[0146] In this case, for example, the insertion openings,
insertion-guiding units, and covering units are formed to be
inclined with respect to the central axis of the holding member
according to the inclination of the central axis of the bottom wall
with respect to the spiral axis of the arc tube. In this case where
the arc tube is inclined with respect to the holding member holding
the arc tube, the insertion openings, insertion-guiding units, and
covering units can have the same positional relationship as that
described in the above embodiments by positioning them based upon
the position of the spiral axis of the arc tube on which the center
of the bottom wall of the holding member is positioned. By doing
so, the same effects as produced in the above embodiments can be
produced.
[0147] Although the above embodiments describe the case where the
central axis of the holding member and the spiral axis of the arc
tube substantially match on the same line, these axes may not
necessarily match. In the case where these axes do not match, too,
the same effects as produced in the above embodiments can be
produced by positioning the insertion openings, insertion-guiding
units, covering units etc. of the holding member based upon the
position of the spiral axis of the arc tube.
2. Shape of Arc Tube
[0148] Although the above embodiments describe the case where the
present invention is applied to an art tube having a double-spiral
structure, the present invention may be applied to arc tubes with
other structures. As one example, the present invention may be
applied to an arc tube composed of a plurality of U-shaped glass
tubes that are connected with one another, e.g., a triple-tube arc
tube composed of three U-shaped glass tubes or a quad-tube arc tube
composed of four U-shaped glass tubes. In this case, however, such
arc tubes need to have end portions at which electrodes are
attached wound around a predetermined vertical axis.
[0149] The end portions of the arc tube may be wound around a
predetermined vertical axis (the spiral axis in the above
embodiments) in such a manner that the end portion is viewed in an
arch-shape from above in the direction of the vertical axis) and is
viewed in an L-shaped from side in the direction perpendicular to
the vertical axis (in the case where the spiral angle is
90.degree.). In this case, the insertion-guiding units (and the
covering units) of the holding member need to be formed in the
direction perpendicular to the above vertical axis. Alternatively,
insertion-guiding units may be formed at the bottom wall in such a
manner that the end portions of the arc tube come in contact, at
only side and bottom surfaces thereof, with the insertion-guiding
units. In this case, too, the ends of the arc tube can be guided to
the insertion openings by rotating the arc tube around the vertical
axis.
[0150] Further, only one of the end portions of the arc tube may be
wound around the spiral axis. In this case, the same effects as
produced in the above embodiment can be produced by the holding
member having the insertion-guiding unit guiding the one end
portion when the arc tube is rotated around the spiral axis. The
end portion of the arc tube referred to herein is such that its
length from the end of the arc tube is at least equal to the length
of the insertion-guiding unit of the holding member in the spiral
direction.
3. Globe
[0151] Although the above embodiments describe the case where the
compact self-ballasted fluorescent lamp does not have a globe
covering the arc tube, the present invention can be applied to a
compact self-ballasted fluorescent lamp that has a globe.
4. Attachment Processes
[0152] The above embodiments describe the case where the holding
member is fixed and the arc tube is moved, in the processes of
attaching the arc tube to the holding member. To be specific, the
arc tube is first moved in the spiral-axis direction and then
rotated around the spiral axis, without moving the holding member.
However, the attachment processes may be such that the arc tube is
fixed and the holding member is moved, or both the arc tube and the
holding member are moved. In either case, the same effects as
produced in the above embodiments can be produced.
5. Others
[0153] Although the above embodiments describe the case where the
present invention is applied to a compact self-ballasted
fluorescent lamp alternative to a 60 W incandescent lamp, the
present invention can be applied to other compact self-ballasted
fluorescent lamps such as those alternative to a 40 W incandescent
lamp and a 100 W incandescent lamp.
6. Low-Pressure Mercury Lamp
[0154] Although the above embodiments describe the case where the
present invention is applied to a compact self-ballasted
fluorescent lamp, the present invention can be applied to other
lamps such as a compact fluorescent lamp shown in FIG. 16.
[0155] The fluorescent lamp 500 includes an arc tube 510, a holder
530, a case 540, a globe 550, and a single base 560 (e.g., a GX10q
type base). The arc tube 510 has a double-spiral structure in which
a glass tube 520 is wound from its middle to its ends. The holder
530 has a closed one end and is in a cylindrical shape. The holder
530 holds the arc tube 510 (specifically, end portions of the glass
tube 520). The case 540 is attached at a peripheral wall of the
holding member 530. The globe 550 covers the arc tube 510. The
single base 560 is attached to a socket of a lighting fixture, and
is supplied with power.
[0156] The fluorescent lamp 500 greatly differs from the compact
self-ballasted fluorescent lamp 1 described in the above
embodiments, in that an electronic ballast is not placed in an
internal space formed by the holding member 530 and the case 540
and the base 560 is not of a screw type, which is the type of bases
typically used for incandescent lamps.
[0157] As in the above embodiments, the holder 530 has insertion
openings, guide grooves, and covering units formed at its bottom
wall. With this construction, the arc tube 520 can be easily
inserted into the holder 530 as in the above embodiments.
INDUSTRIAL APPLICATION
[0158] The present invention applicable to a low-pressure mercury
lamp can be utilized for enabling ends of an arc tube to be easily
inserted into a holding member.
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